468 HYDROPHOBIA. 



Thus, both from the clinical and histological standpoints, 

 the nervous system is the centre of the disease. Experi- 

 mental pathology confirms this view by finding in the 

 nervous system a special concentration of what, from want 

 of a more exact term, we must call the hydrophobic virus. 

 Earlier inoculation experiments with material from various 

 parts of animals dead of rabies, had not given uniform 

 results, as whatever was the source of the material, the 

 disease was not invariably produced. Such experiments 

 had been made by subcutaneous injection. Pasteur's first 

 contribution to the subject was to show that the most 

 certain method of infection was by inserting the infective 

 matter beneath the dura mater. Not only was the disease 

 invariably produced where materials from certain sources 

 were thus used, but the natural period of incubation was 

 shortened. It was then found that in the case of any 

 animal or man dead of the disease, injection by the above 

 method, of emulsions of any part of the central nervous 

 system, of the cerebro-spinal fluid, or of the saliva, gave rise 

 to rabies ; and, further, the identity of the furious and para- 

 lytic forms was proved, as sometimes the one, sometimes 

 the other, was produced, whatever form had been present 

 in the original case. Infection with the blood of rabic 

 animals does not reproduce the disease. There is evi- 

 dence, however, that the poison also exists in such glands 

 as the pancreas and mamma. Subcutaneous infection with 

 part of the nervous system of an animal dead of rabies 

 usually gives rise to the disease. 



In consequence of the introduction of this more reliable 

 inoculation method, further information has been acquired 

 regarding the spread and distribution of the virus in the 

 body. Gaining entrance by the infected wound, it early 

 manifests its affinity for the nervous tissues. It reaches the 

 central nervous system by spreading up the peripheral 

 nerves. This can be shown by inoculating an animal sub- 

 cutaneously in one of its limbs, with virulent material. If 

 now the animal be killed before symptoms have manifested 

 themselves, rabies can be produced by subdural inoculation 



